1. Field of the Invention
The present invention relates to a light source apparatus, and an image display apparatus and a television receiving apparatus comprising the light source apparatus.
2. Description of Related Art
As for an image display apparatus, for example, a liquid crystal television, there are two types: a behind type in which a fluorescent tube is arranged as a back light on a flat surface behind a liquid crystal display panel displaying an image; and an edge type in which a fluorescent tube is arranged at one side of a backlight plate or fluorescent tubes are arranged at two sides of the backlight plate and light coming to the backlight plate is emitted to a liquid crystal display panel. However, not only the behind type image display apparatus but also the edge type image display apparatus utilizes the fluorescent tube as described above, and has problems that rise in temperature is not uniform and that efficiency for light utilization is low.
In view of these problems, a light emitting diode (LED) is recently utilized as the back light, instead of the fluorescent tube. However, the LED cannot provide a large amount of luminescence with respect to an amount of supplied current. Thus, it causes a problem that an amount of heat becomes larger with respect to the amount of luminescence and the larger amount of heat shortens the life of the LED.
Patent Document 1 discloses a display apparatus that includes a mount board on which plural light emitting fixed elements, a circuit supplying drive current to them and a thermal conductive film conducting heat generated by the plural light emitting fixed elements are mounted, wherein the mount board is fixed by a screw to a frame on which the mount board should be arranged, and that can conduct heat coming from the thermal conductive film to the frame.
Since a liquid display apparatus does not have a larger space occupancy for a room with respect to the size of a display screen, it is possible to efficiently utilize the limited space of the room. Thus, the liquid display apparatus is widespread. The liquid crystal display apparatus is configured to emit light from a light source accommodated in a back cabinet toward a liquid crystal display panel arranged inside a front cabinet for displaying an image, in order to display the image. A cold cathode fluorescent tube is conventionally utilized as the light source. However, a LED is recently utilized as the light source, because the LED facilitates partial control of brightness on the screen, high speed flash control for preventing so-called a blur of moving image, and the like. Thus, the LED is well utilized in recent years.
Patent Document 2 discloses a display apparatus in which a radiator plate is arranged on a back cabinet and a LED board mounting a LED on one surface is fixed to the radiator plate by a screw. The display apparatus makes the radiator plate conduct heat generated by the LED board, to cool the LED board.
The display apparatus includes: a display panel (for example, a liquid crystal display panel) whose display surface displaying an image is arranged at the front side; a light source apparatus (a so-called back light) that is arranged behind the display panel and lights the display panel; and a cabinet accommodating the display panel and the light source apparatus. A heat exhaust hole is formed on the cabinet.
The light source apparatus includes plural circuit boards in matrix arrangement, which are assisted by assist members. A light emitter (for example, a LED) is mounted on each circuit board.
Each circuit board is fixed to the assist member by plural rivets. A push rivet is utilized as an example of the rivet (See Patent Document 3). Thus, threaded holes are formed on the circuit board and assist member at the corresponding positions, and the push rivet is inserted into the threaded holes.
Generally, the color of push rivet is white. The reason is that the light generated by the light emitter should be reflected toward the display panel side.
In addition, it is known that a circuit board mounting a LED is fixed to an assist board by adhesive (See Patent Document 4).
Patent Document 1: Japanese Patent Application Laid-Open No. 2007-311561
Patent Document 2: Japanese Patent Application Laid-Open No. 2006-58487
Patent Document 3: Japanese Patent Application Laid-Open No. H9-138408
Patent Document 4: Japanese Patent Application Laid-Open No. 2008-166304